May 16, 2020

Construction firms ‘most optimistic’ about economy and Brexit, research shows

Business Census 2017 report.
Company Check
Katie Deverill
Company Check
Catherine Sturman
3 min
Construction firms ‘most optimistic’ about economy and Brexit, research shows
The construction industry is more optimistic about the economy this year than other sectors after experiencing a less negative impact from Brexit - that...

The construction industry is more optimistic about the economy this year than other sectors after experiencing a less negative impact from Brexit - that’s according to the findings of a newly published Business Census 2017 report.

The annual survey of 1,300 firms, carried out by the business data website Company Check during November and December, revealed that more than half (66 percent) were optimistic about the UK economy in 2017, higher than any other major industry in the survey.

That figure compared to 63 percent in professional services, 59 percent in manufacturing and 49 percent in tech. Only the food and drink industry was higher, yet accounting for just 4 percent of all companies questioned.

When asked about Brexit, just a quarter of construction firms said the vote to leave had had a negative impact on their business. 11 percent said the impact had been positive while 61 percent said it had made no difference; higher than any other.

Katie Deverill, from Company Check, said: “The Business Census lets us ‘take the temperature’ of the UK’s construction industry to understand the big challenges they’re going to be facing during the next 12 months. The findings show Brexit hasn’t had the chilling effect that it’s had in other areas, with high levels of optimism for the year ahead.

“However, there’s also high levels of disaffection with local authorities when it comes to them supporting and nurturing business growth. The powers that be should take note of these figures and recognise that something in the current system just isn’t working.”

Compared to 64 percent of construction companies who said they grew in 2016, 74 percent said they expected to grow this year. Across all industries that figure was 73 percent While just 18 percent said they feared economic decline next year, making it the most optimistic industry.

Construction Industry Council Chairman Prof John Nolan has commented on these results saying, “I am not at all surprised by these figures. My practice registered a substantial boom in new enquiries immediately following the EU referendum result and that level of increased enquires has continued. Most of my peers in Built Environment Professions have also reported an increase in enquires. Our biggest concern now is finding sufficient quality staff to meet this increased demand.”

More businesses in construction said they were affected by the issue of recruitment last year than any other industry (25 percent) and the same is true for 2017, albeit at a lower 14 percent.

34 percent said the economy was the biggest concern this year, while 30 percent said politics. Nationally, concerns about political events almost doubled compared to 2016 for all sectors, with it being named the biggest challenge ahead by one in three (30 percent) an increase of 90 percent on the year before.

When asked whether they thought local government was doing a good job of supporting business growth, just a quarter of construction firms said ‘yes’. This compares to 44 percent in finance, 35 percent in professional services and 33 percent in tech.

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Read the January 2017 issue of Construction Global here

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Jun 17, 2021

Why engineers must always consider human-induced vibration

Vibrations
Engineering
design
Structuralintegrity
Dominic Ellis
3 min
Human-induced vibration can lead to a number of effects upon the structure and its users

Human induced vibration, or more accurately vibrations caused by human footfall, often conjures images of Millennium Bridge-style swaying or collapsing buildings.

But in reality, the ‘damage’ caused by human-induced vibrations is less likely to ruin a structure and more likely to cause discomfort in people. Though not as dramatic as a structural failure, any good engineer wants to make sure the people using their structures, be it bridges or buildings or anything in between, can do so safely and comfortably. This is why human-induced vibration must be considered within the design process.

Resonance v Impulse

There are two ways that human-induced vibrations affect structures: resonant, and impulse or transient response. Put simply, resonance occurs when Object A vibrates at the same natural frequency as Object B.

Object B resonates and begins to vibrate too. Think singing to break a wine glass! Although the person singing isn’t touching the glass, the vibrations of their voice are resonating with the glass’s natural frequency, causing this vibration to get stronger and stronger and eventually, break the glass. In the case of a structure, resonance occurs when the pedestrian’s feet land in time with the vibration.

On the other hand, impulse or transient vibration responses can be a problem on structures where its natural frequencies are too high for resonance to occur, such as where the structure is light or stiff. Here the discomfort is caused by the initial “bounce” of the structure caused by the footstep and is a concern on light or stiff structures.

Engineers must, of course, design to reduce the vibration effects caused by either impulse or resonance.

Potential impacts from human induced vibration

Human induced vibration can lead to a number of effects upon the structure and its users. These include:

  • Interfering with sensitive equipment Depending on the building’s purpose, what it houses can be affected by the vibrations of people using the building. Universities and laboratories, for example, may have sensitive equipment whose accuracy and performance could be damaged by vibrations. Even in ordinary offices the footfall vibration can wobble computer screens, upsetting the workers.
     
  • Swaying bridges One of the most famous examples of human-induced resonance impacting a structure occurred with the Millennium Bridge. As people walked across the bridge, the footsteps caused the bridge to sway, and everybody had to walk in time with the sway because it was difficult not to. Thankfully, this feedback can only occur with horizontal vibrations so building floors are safe from it, but footbridges need careful checking to prevent it.
     
  • Human discomfort According to research, vibrations in buildings and structures can cause depression and even motion sickness in inhabitants. Tall buildings sway in the wind and footsteps can be felt, even subconsciously by the occupants. It has been argued that modern efficient designs featuring thinner floor slabs and wider spacing in column design mean that these new builds are not as effective at dampening vibrations as older buildings are.
     
  • Jeopardising structural integrity The build-up of constant vibrations on a structure can, eventually, lead to structural integrity being compromised. A worse-case scenario would be the complete collapse of the structure and is the reason some bridges insist that marching troops break step before crossing. Crowds jumping in time to music or in response to a goal in a stadium are also dynamic loads that might damage an under-designed structure.

How to avoid it

As mentioned, modern designs that favour thinner slabs and wider column spacing are particularly susceptible to all forms of vibration, human-induced or otherwise, but short spans can also suffer due to their low mass. Using sophisticated structural engineering software is an effective method for engineers to test for and mitigate footfall and other vibrations at the design stage.

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